1. Field of the Invention
The present invention relates to a magnifying observation apparatus such as a digital microscope or a microscope which captures and displays a magnified image, a magnified image observing method, a magnified image observing program, and a computer-readable recording medium.
2. Description of Related Art
As a magnifying observation apparatus that magnifies and displays an image of a subject being a specimen such as a micro-object, a workpiece or the like, there has been used an optical microscope, a digital microscope or the like which uses an optical lens. In the digital microscope, a specimen as an observation target placed on a stage is irradiated with illumination light via an optical system, reflected light or transmitted light from the specimen is received in an imaging element such as a CCD or a CMOS where the light is electrically read at each of two-dimensionally arranged pixels, and the electrically read image is displayed on a display section such as a display (e.g., JP 2012-145722 A). In such a magnifying observation apparatus, an optical lens, made opposed to the stage, is moved in a z-axis (height) direction to adjust a focus. Generally, the movement in the z-axis direction is performed by a head section integrally formed by the lens and a camera.
In such a magnifying observation apparatus, there is known depth synthetic processing (also called “focus synthesis”, “multi-focus”, etc.) where a plurality of images are photographed as positions of the lens and the specimen are changed in the z-axis direction with respect to an image with a small depth of focus, and pixels in focus are extracted from the obtained images, to synthesize one image (depth synthetic image). However, for performing the depth synthetic processing on images with more than 1 million pixels in order to obtain such a depth synthetic image (also called “focused image”, “multi-focus image”, etc.), a processing load becomes large and required storage regions also increase, to make specifications for hardware strict. Accordingly, as shown in a flowchart of FIG. 36, the processing has hitherto been subdivided to serially repeat operations of movement of a z-position of the lens, photographing and synthesis, thereby controlling the z-position movement, the photographing and the synthesis such that they are synchronously performed.
According to this method, the z-position of the lens does not move until completion of the synthesis processing. Further, with this method, as shown on a user interface screen of FIG. 37, a user needs to previously specify an upper limit position and a lower limit position of a range where the lens is moved in the z-direction, which has caused a problem of taking time.
Alternatively, there is also a method where depth synthesis is started after movement of the z-position of the lens to a depth synthesis start position (initial position), the z-position is moved by a predetermined distance in one direction, the user checks a synthesis progress image, and at the point of completion of desired synthesis, the processing is specified to be completed. With this method, however, when a setting of a synthesis range is failed, for example when the upper limit of the synthesis range is erroneously set lower than a correct position, it is of necessity to re-set the upper limit position and the lower limit position and repeat the synthetic photographing processing from the start, which is inefficient.
Further, in these methods, for example when a synthetic image is to be captured at each position, as shown in FIG. 38, the camera at a certain position is first moved in the height direction, namely the z-direction, to capture images with different heights, these images are then synthesized to extract pixels at focused positions, the stage is moved to a next position, and the camera is similarly moved in the z-axis direction to synthesize images. By repeating these operations, synthetic images which are in focus even at portions with different heights have been generated. With this method, however, the stage is moved after a focused image is obtained at each position, which has caused a problem of taking extremely a long time. Since the image synthesis processing especially takes a long time, even when the photographing operation itself is completed in a short time, the waiting time during the imaging and movement for the synthesis processing occurs, which has caused a problem of taking still a longer time.